38. Reactive Air Brazing of LSCoF and Alumina with Ag-V2O5 Alloys for SOFC Applications

  1. Dongming Zhu and
  2. Kevin Plucknett
  1. N. M. Zink1,
  2. A. M. Meier1,
  3. K. S. Weil2 and
  4. J. S. Hardy2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291238.ch38

Advances in Ceramic Coatings and Ceramic-Metal Systems: Ceramic Engineering and Science Proceedings, Volume 26, Number 3

Advances in Ceramic Coatings and Ceramic-Metal Systems: Ceramic Engineering and Science Proceedings, Volume 26, Number 3

How to Cite

Zink, N. M., Meier, A. M., Weil, K. S. and Hardy, J. S. (2005) Reactive Air Brazing of LSCoF and Alumina with Ag-V2O5 Alloys for SOFC Applications, in Advances in Ceramic Coatings and Ceramic-Metal Systems: Ceramic Engineering and Science Proceedings, Volume 26, Number 3 (eds D. Zhu and K. Plucknett), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291238.ch38

Author Information

  1. 1

    School of Engineering at Alfred University 2 Pine St Alfred, NY 14802

  2. 2

    Pacific Northwest National Laboratory 902 Bateüe Blvd. MS K2-44 Richland, WA 99352

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2005

ISBN Information

Print ISBN: 9781574982336

Online ISBN: 9780470291238

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Keywords:

  • ceramic;
  • oxygen;
  • cathode;
  • electrodes;
  • environment

Summary

The feasibility of brazing LSCoF ceramic substrates with silver-vanadium pentoxide (Ag-V2O5) alloys for use in solid oxide fuel cell (SOFC) applications was studied. Preliminary testing was also performed on the Ag-V2O5/alumina (Al2O3) system in order to determine the feasibility of brazing LSCoF to Fecralloy™ with an Ag-V2O5 alloy since an AI2O3 layer is formed on the Fecralloy surface prior to brazing. Sessile drop tests were performed using liquid Ag with 1 to 20 weight percent (wt%) V2O5 additions at either 1000 or 1100 °C. Similar to previous results for Ag-CuO alloys, additions of V2O5 resulted in a decrease in the apparent contact angle and a transition from non-wetting to wetting behavior for both substrate materials. Mechanical test samples were fabricated by brazing using Ag with 1, 2 and 5 wt% VJOJ additions. For the Ag-V2O5/LSCoF samples, the joint fracture strengths ranged from 10 to 30% of the monolithic LSCoF fracture strength (σjoint = 26 ± 9 MPa versus σLSCoF = 151 ± 24 MPa). An SEM/EDS microstructural analysis of the brazed cross-sections indicated the formation of a vanadium rich reaction product at the braze/LSCoF interface. It is hypothesized that the reaction product provided improved chemical bonding at the interface that resulted in the modest joint strengths. In the the Ag-V2O5/ Al2O3 system, although the contact angles were less than 90°, all of the brazed AI2O3 samples failed to bond during brazing or fractured during sample preparation. These poor adhesion results indicate potential problems with the Fecralloy™/Ag-V2O5/LSCoF system.